So you admit that there is no research showing that healthy people on bed rest perform abnormally on the 2 day CPET. There is only your suspicion, which is contradictory to the existing evidence. Deconditioned controls and other healthy people do a bit better on day 2. There is no reason to suspect that healthy people with an even greater degree of deconditioning function in a diametrically different manner from patients with a lesser degree of deconditioning. While such a thing might be marginally possible, it's extremely dishonest to claim it as being proven.Dear Professor Edwards, there isn't an exact replication study of "2 day CPET" per se, since that exact protocol is a new idea, Pacific Labs?. However, there is a body of literature on inflammatory markers 24h post-exercise in bed-rested subjects, both human and animal. These studies show convincingly that bed rest results in an inflammatory cascade, and fall in peak VO2, not otherwise seen in sedentary controls or normal subjects. Since the claim from Pacific Labs is a potentially important one, I don't think their conclusions are sound until deliberately bed rested healthy controls are tested accordingly.
The relevant studies, which you obviously haven't read, clearly state that VO2max was achieved, meaning that objective indications of maximal effort were met. This includes heart rate near or at predicted max, respiratory quotient of 1.1 or higher, and a third one I can't remember. Maybe you should read the studies so that you can critique them without making embarrassingly inaccurate comments about them.We also have to be very careful about the use of the term "VO2max". True VO2max is not easily achieved on exercise stress testing (even in healthy subjects) and often a surrogate term, "peak VO2 achieved" is substituted and the terms used interchangably. These are not the same measures at all.
I believe that non-max testing has been used for more seriously afflicted patients, and those who are unwilling to risk a long-term relapse. And there is probably research in the works to see how well non-maximal testing matches up with maximal testing, to see if it's feasible to test patients in that matter without half killing them in the process.Please examine the data from CFS exercising stress testing, in some of these studies 0% of subjects were willing/able to exercise to 85% maximum heart rate, some subjects achieving only 120bpm. Thus, as per the NY association of cardiologists guidelines, these exercise stress tests should be void.
But the research papers people are referring to here as proof of a pathological reaction to exertion were ones where VO2max was used in the typical and appropriate manner.
Since when do patients have to reach a certain speed for the CPET to be valid?Let us also think logically about this for a moment, on the PACE trial the patients could only walk 300 metres in 6 minutes (1.8mph), yet on VO2max exercise stress testing one has to achieve at least 3.2mph at 6 minutes to reach a valid VO2max.